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Abstract:
Huang, 1982 and ?L. dorsotuberosa f. postilirata sensu Pang, 1985), were collected from two sediment cores
from Lake Nam Co, on the central Tibetan Plateau. Two variants of LA–ICP–MS (laser ablation–inductively
coupled plasma–mass spectrometry), spot and line-scan analyses, were used to investigate trace element concentrations
(Mg, Sr, Ba, U and rare earth elements [REEs]) in single ostracod shells. The results suggest that the
line-scanmethod can provide better precision than the spot analysis and is therefore preferred.No significant difference
in trace element composition between taxawas detected in our study. Fluctuations ofMg/Ca and Sr/Ca in
the shells showgood agreement with the reported lake level changes during the Holocene, indicating that ostracod
Mg and Sr can be related to palaeohydrochemical processes in this area. A high correlation between Ba/Ca
and Sr/Ca was detected in our study, perhaps implying that both metals were controlled by the same mechanisms.
A possible relationship between ostracod U/Ca and the past redox conditions on the lake bottom is
discussed. Relatively low and constant La/Ca was observed, which could be due to the REE characteristics in
the lake water, or ostracod biological processes, or even the associated Fe–Mn and/or organic contaminants. Future
studies on more specimens fromthis area, especially shells fromliving ostracods, are essential to investigate the potential of ostracod Ba, U and REEs for use as palaeoenvironmental indicators
